Laboratory and Surveillance

Mosquito surveillance is an essential component of an Integrated Pest Management Program (IPM) and a considerable amount of effort is devoted to conducting adult and immature mosquito surveillance. Our program consists of locating breeding sources and monitoring mosquito populations and disease activity over time and space. We collect and analyze data on abundanceof mosquito species, we monitor distribution patterns of the different mosquito species, determine risk periods of public exposure to mosquito-borne diseases, and evaluate mosquito control activities.

We use a variety of traps for our surveillance efforts. American Light traps, which collect mosquitoes and other insects, attracted to the light produced by this trap, Mosquito Magnet® traps, which capture host-seeking mosquitoes that are attracted to the carbon dioxide produced from burning liquid propane and Gravid female traps which attract female mosquitoes that are looking to lay eggs. These traps are set in sites of all habitats throughout Sacramento and Yolo counties. Our interactive map displays the general locations of our weekly traps and how many female mosquitoes were collected during the most recent cycle.

West Nile Virus Surveillance
Mosquitoes are trapped and collected from the field and brought back to the lab where the collected females are pooled together by species. Each pool contains from one to 50 mosquitoes per pool. Each sample is tested for West Nile virus, St. Louis Encephalitis, and Western Equine Encephalomyelitis. Aside from mosquitoes, we also use sentinel chickens to help us track virus activity. By strategically placing sentinel flocks of chickens at unique locations within Sacramento and Yolo counties we are able to monitor and track virus activity. Within a few days after having been bitten by a mosquito infected with a virus the chickens develop specific antibodies to that virus. They do not become ill or die. Blood samples from the chickens are routinely taken by laboratory staff and tested for the presence of these antibodies. Typically, the chickens are sampled every other week during the mosquito season (May until October) and once a month during November until April.

If the presence of these antibodies is confirmed by the California Department of Public Health laboratory there is an increased potential risk that these viruses could be transmitted to wildlife, equines or humans.

Did you know?
In the interest of science, Arctic researchers uncovered their chests, arms, and legs and reported as many as 9,000 mosquito bites per person, per minute. At this rate, an unprotected human would lose one half of his or her blood supply in approximately 2 hours! That's amazing!